A lens applied to an LED lamp comprises a lens body (1) in which an LED light source accommodating space (2) is arranged. The LED light source accommodating space (2) is provided with an incident lateral face (3) and an incident bottom face (4), the incident lateral face (3) and the incident bottom face (4) enabling light to enter the lens body (1). A rare-earth fluorescent powder coating (5) or a quantum dot fluorescent powder coating (6) is coated on both the incident lateral face (3) and the incident bottom face (4). A blue light LED is arranged in the LED light source accommodating space of a single combined lens or a plurality of combined lenses so as to obtain various types of white light. If the quantum dot fluorescent powder is used, high-efficiency white light can be converted into high-light-efficiency warm white light.
